I agree completely with all of your suggestions, I feel the exact same way, especially with the problems with Brax and Ricky. I'm also annoyed at the way they just shoved Brody aside just so the show can have Dean and Ziggy.
For myself, I would say Hunter and Olivia. Probably due to my dislike for Hunter, but I could never stand the pair together on screen.
Ash and Tori. It was just another boring, overdone example of "professional woman falling for bad boy", and they were on and off all the time, I never took them seriously as an actual couple.
Andy and Hannah. Dear Lord... (Though from what I've seen, they may not be the most popular).
Kyle and Phoebe- mainly because I felt like Tamara and Kyle were a better fit back in 2014, and I was just bitter that the show runners didn't go with it.
Speaking of... Casey and Tamara. Honestly I preferred Casey and Sasha, but just me.
Kat and Robbo- I'm not sure why, but I feel like they jumped Kat into another troubled relationship waaay too quickly. Again, my dislike of Kat also played a role.
Matt and Maddy- I didn't dislike them as a couple, but I didn't really understood all the hype between the two, particularly since I always thought Oscar and Maddy were more suitable.
Josh and Evie- A big fan of both characters, but I wasn't at all too keen on the circumstances of how they got together.
Indi and Romeo- same as above, I feel like they were hyped too much for me to like them.
Aden and Nicole and Oscar and Skye.
Now, of course if you like any of the couples above, that's great. But I never could find it in myself to invest in it.